Author(s)

Ka Lin^1,2, Decheng Li^1*, Ganlin Zhang¹, Yuguo Zhao¹, Jinling Yang¹, Feng Liu¹, Xiaodong Song¹

¹State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
²University of the Chinese Academy of Sciences, Beijing, China.

The parental material of soils in the Qilian Mountains of northwest China is mainly aeolian loess containing CaCO₃ which may remain in soils under the semiarid-arid climate. To disclose the CaCO₃ characteristics change with the altitude and the terrain attributes, we surveyed 18 soil profiles in an altitude sequence from 3076 m to 4510 m in the Hulugou Watershed in the Qilian Mountains, measured CaCO₃ contents of all genetic horizon samples, analyzed the densities, illuviation modes and depths of CaCO₃ in the profiles, extracted values of the terrain attributes of the profiles including altitude slope, aspect, plane curvature, profile curvature and terrain wetness index (TWI) from the 90 m resolution SRTM3 DEM data on ArcGIS 9.3 platform. We found that CaCO₃ weighted content of the profiles ranged from 1.30 g·kg^-1 to 93.09 g·kg^-1, CaCO₃ density from 0.05 kg/m² to 75.69 kg/m², CaCO3 illuviation depth from 12 cm to 54 cm. CaCO₃ illuviation modes could be divided into three types, i.e., no illuviation mode in which the profile has only A horizon or CaCO₃ content < 5 g·kg^-1, middle illuviation mode in which CaCO₃ accumulated in a middle horizon, and down illuviation mode in which CaCO₃ content increases with the depth. CaCO₃ weighted content, density and illuviation depth had significant correlation with certain terrain attributes. In general, the altitude sequence is an effective way to study CaCO₃ characteristics in the alpine region, and the data of terrain attributes which can influence the precipitation and its redistribution in soil are potential in predicting soil CaCO₃ characteristics in the alpine region.

CaCO3, Altitude Sequence, Terrain Attributes, The Hulugou Watershed, The Qilian Mountains

Lin, K. , Li, D. , Zhang, G. , Zhao, Y. , Yang, J. , Liu, F. and Song, X. (2017) Content, Density, Illuviation Mode and Depth of CaCO₃ in Soils of Semiarid-Arid Qilian Mountains—An Altitude Sequence Study of the Hulugou Watershed. Agricultural Sciences, 8, 479-491. doi: 10.4236/as.2017.86036.